The present invention relates to a fuse of a semiconductor device, and a method for forming the same.
If at least one memory cell of a memory array of a semiconductor device has a defect due to fabrication of the semiconductor device, the whole device is regarded as being defective and discarded, thereby degrading the device yield. To overcome this problem, the semiconductor device is designed with redundancy cells so that a defective cell may be replaced with a redundancy cell resulting in repair of the whole memory, thereby improving yield.
The repair operation with a redundancy cell is performed to identify a defective memory cell through a test after wafer processing and to replace the corresponding address with an address signal of a spare, redundancy cell. When an address signal corresponding to a defective line is inputted, the defective line is substituted by a redundancy line.
In order to perform the above repair process for repairing the defective circuit, after a semiconductor device is fabricated, an oxide film over a metal fuse is removed to open a fuse box, a laser is irradiated into the corresponding metal fuse to cut a metal fuse. A wire disconnected by irradiation of the laser is referred to as a metal fuse, and the disconnected site and its surrounding region are referred to as a fuse box.
FIG. 1 is a diagram illustrating a conventional fuse of a semiconductor device, and a conventional method for forming the same. A first interlayer insulating film 100 is formed over a semiconductor substrate (not shown) having a lower structure. A plurality of metal fuses 110 are formed over the first interlayer insulating film 100. The metal fuse is formed to have a line type.
A second interlayer insulating film (not shown) is formed over the first interlayer insulating film 100 and the metal fuse 110. A part of the second interlayer insulating film (not shown) is etched to form a fuse open region. A part of the second interlayer insulating film (not shown) remains on the metal fuse 110.
One of the metal fuses 110 is selected, and a laser blowing process is performed on the selected metal fuse 110. A region disconnected by the laser blowing process is defined as a fuse blowing region 110a. 
When an energy is applied to the fuse blowing region 110a in the laser blowing process, a crack is generated in the second interlayer insulating film (not shown) that remains on the fuse blowing region 110a by a heat generated from the laser. The second interlayer insulating film (not shown) that remains on the metal fuse is removed to cut the metal fuse, which is vaporized in the air.
In the above-described fuse of the semiconductor device and method for forming the same, heat generated in the laser blowing process conducts away from the fuse out into the metal line, so that it is difficult to concentrate enough heat to cut the metal fuse. As a result, the metal material of the fuse is not completely vaporized, and un-vaporized metal materials remains resulting in the fuse not being cut.